This invention lies in the field of seismic prospecting and is more specifically in the field of apparatus for generating elastic (seismic) waves in the earth. Still more specifically it concerns such apparatus in which the vibrator is mounted on a vehicle, and the mass of the vehicle serves as the reaction mass for the vibrator.
In the prior art vibrators have always carried their own reaction mass, separate from the mass of the carrying vehicle, such as a truck . In applicant's U.S. Pat. No. 3,789,951 and copending application Ser. No. 296,670 the concept of using the truck mass for the reaction mass has been shown. However, even these systems require hydraulic means, separate from the vibrator itself, for raising the truck and supporting it on top of the base plate, while the vibrator is operating, and then lowering the truck, and using the same hydraulic means to lift the base plate and the vibrator, while the truck is traveling.
The use of a heavy base plate is a disadvantage, which adds cost to the devices, and reduces (by its mass) the output of the vibrator into the earth. Further the hydraulic system is an added cost and weight, which in this invention is eliminated.